Both of these titles follow the development of a romantic relationship between two people who end up living with each other. Both titles are generally light-hearted in tone, but also feature drama as a means of progressing plot.
Authored by the same mangaka, the execution of the two series share highly similar traits. For instance, the male protagonist is a salary-man who is subjected to a plethora of obstacles before attaining the female lead's heart.
Both deal with a similar premise where the main male lead is forced to live with a stranger while he is currently seeing someone. Orange Yane is much more light-hearted and takes a completely different path for the plot while Mama wa Doukyuusei is focused on drama and controversy.
Both stories start out with 2 people ending up in the same building (block) with an awkward feeling at start but then they get to know eachother better over time.
Senakagurashi is about 2 young people while Orange Yane no Chiisana le is about 2 adults with kids.
Both the male and female main characters live together but Orange Yane no Chiisana Ie is more concentrated on slice of life, romance and family while love lucky is conecentrated on ecchi, troubles of a celebrity having a marriage and romance.
Both manga have a male lead who's forced to live with a woman they don't know.
In both cases the female lead is adorable but the contact at first doesn't go very smooth. This changes over time.
The characters themselves are quite different, Orange Yane no Chiisana Ie is about 2 adults with their own kids while Re:Marina is about a 16yo guy and a woman of a few years older.
More info would spoil the story, just given both a try ;)